I mean, you can get to and from practically any airport by bike if you're determined enough.

World of difference between using cycling infrastructure and sharing roads with 2 ton beasts powered by paleo compost.

Sure but to Schiphol (and any other airport in NL obviously) there's a proper bicycle lane.

There are bicycle lanes everywhere in Holland. I don't know a single person that bikes to the airport. From Amsterdam its at least 30 minutes by bike from the city center. Actually have no idea where I would park the bike. It's not common and not practical at this point.